A variety of conditions may negatively affect the human knee including arthritis, ligament instability, and localized trauma. These conditions may be surgically treated by repairing portions of the knee cartilage, meniscus, or ligaments or by replacing them with natural or artificial replacements. In such procedures, it is often necessary to correct the alignment of the knee to relieve pressure from the damaged portion of the joint and balance the load on the joint. In some instances, correcting the knee alignment alone, without additional repair or replacement of injured or diseased tissue, is sufficient to provide relief and improve function. Often, in a young arthritis patient, correcting the knee alignment may be a first surgical choice to provide years of relief prior to resorting to a more aggressive total knee replacement procedure. Typically, injured or diseased knees will develop a varus deformity in which the medial side of the person's knee joint has become compressed resulting in a bowlegged alignment of the lower limb.
A frequently used procedure to correct knee alignment is high tibial osteotomy. In this procedure, the knee alignment is changed by cutting the tibia on one side and then expanding or compressing the cut side to change the angle between the axes of the tibia and femur. For example, in a closing high tibial osteotomy, a wedge of bone is removed from the tibia and then the opposite sides of the cut are brought together to angle the tibia towards the side on which the cut was made. In an opening high tibial osteotomy, a cut is made partway across the tibia and the cut is opened to create a wedge-shaped gap thereby angling the tibia away from the side on which the cut was made. A fixturing device, such as a bone plate or external fixator, is then applied to the tibia to hold the tibial alignment until the bone heals. Typically, for opening high tibial osteotomy, bone is taken from the patient's pelvis and applied to the gap in the tibia to aid in bone healing. An opening high tibial osteotomy may be performed on the medial side of a patient's knee to treat a varus deformity.
Another procedure used to correct knee alignment is a distal femoral osteotomy. For example, in an opening lateral distal femoral osteotomy, a cut is made partway across the femur from the lateral side and the cut is opened to create a wedge-shaped gap thereby angling the femur away from the lateral side.